Process for preparation of anthraquinones and fluorenones

ABSTRACT

A process is disclosed for producing cyclized aromatic compounds by the liquid-phase air oxidation of 2-methyl-substituted biphenyls and diphenylmethanes in an acetic acid medium in the presence of a cobalt-manganese-bromine catalyst or a zirconium-cobalt-manganese-bromine catalyst wherein the mole ratio of cobalt-to-manganese is about 1.0:0.1 to about 1.0:10.0 and the ratio of zirconium-to-cobalt is about 0.005:1.0 to about 0.20:1.0, and mole ratio of bromine to total metals of said cobalt-manganese-bromine catalyst or zirconium-cobalt-manganese-bromine catalyst is from about 0.2:1.0 to about 20.0:1.0, which process comprises conducting the reaction in a batch process at a temperature of from 75° C. to about 250° C. at a pressure of from 1 to 100 atmospheres, or continuously in two stages comprising a first-stage reaction at a temperature of about 75° C. to about 200° C. and a second-stage reaction at a temperature of about 150° C. to about 250° C. and recycling the cobalt-manganese catalyst or the zircnium-cobalt-manganese catalyst by oxalate precipitation of the catalyst at temperatures of about 110° C. to about 200° C. prior to the separation of mother liquor and using about 0.25 to about 2.5 moles of oxalic acid per mole of cobalt and manganese or mole of zirconium-cobalt-manganese and continuously recycling the recovered catalyst metals to the oxidation stages. The products of this novel process, anthraquinones and fluorenones, are useful for the manufacture of dyestuffs and pharmaceuticals.

FIELD OF THE INVENTION

This invention relates to a process for the preparation ofanthraquinones and fluorenones and their substituted derivatives.

BACKGROUND OF THE INVENTION

In general, the common methods of synthesis of ketones can be dividedinto (1) synthesis from acid halides and organometallic compounds, (2)synthesis from carboxylic acids, (3) Friedel-Crafts reactions, and (4)enolate condensations.

Synthesis from acid halides and organometallic compounds has beenextensively used but costs of the organometallic reagents are relativelyexpensive and care must be used in handling. The use of carboxylic acidsand their salts for ketone synthesis suffers from the disadvantage thatthe method will produce in general only the symmetrical ketones in goodyields. The Friedel-Crafts acylation reactions generally give goodyields. However, their use is restricted by the orientation of the acylgroup introduced and the metal halides are expensive with attendantwaste disposal problems. Enolate condensations give a variety ofproducts; however, the overall yields are frequently not so good asthose that can be obtained by other methods, and procedures frequentlyare more involved.

For example, as is well-known, the important methods of formation ofbenzophenone, i.e., benzophenone and its substituted derivatives, arethe following: (1) oxidation of diphenylmethanes or benzohydrols, e.g.,by chromic acid or by oxygen in presence of a catalyst, for example, asis taught in U.S. Pat. No. 2,859,274; (2) hydrolysis of ketonechlorides; (3) condensation of benzoyl halides with benzene, itshomologues, and substituted derivatives having a reactive position, inpresence of AlCl₃ or other catalyst, or under high pressure, as taughtin U.S. Pat. No. 2,528,789; (4) reaction of a benzonitrile (or benzoylhalide) with a phenylmagnesium halide; (5) distillation of calcium orother suitable benzoate (Ann 12, 41).

Preparation of anthraquinone specifically has been proposed by severaldifferent processes: (1) the DielsAlder reaction of butadiene on1,4-naphthoquinone, (2) oxidation of anthracene in the presence ofcatalysts, (3) Friedel-Crafts reaction with benzene and phthalicanhydride, (4) oxidation of suitable precursors such as indane. In theFriedel-Crafts process, since a large amount of aluminum chloride isnecessary, disposal of the wastes from the process is difficult.Furthermore, since isomerization reactions, rearrangement reactions, andelimination reactions occur in the process, many by-products derivedfrom these reactions contaminate the product. Oxidation of anthracene iseconomically accomplished only when relatively pure anthracene isavailable at moderate costs. The Diels-Alder reaction suffers from thehigh cost of naphthoquinone. U.S. Pat. Nos. 3,699,134; 3,872,134;3,872,135; 4,002,653; 4,036,860; 4,036,861; and 4,215,063 teach typicalprocesses for manufacture of anthraquinone by oxidation ofdiphenylmethane compounds. These processes produce many by-products.

Preparation of fluorenones has been proposed by several differentprocesses also: (1) the heating of salts of diphenyl-o-carboxylic acidor its salts produces fluorenone, (2) the diazonium compound ofo-amino-benzophenone gives fluorenone with evolution of nitrogen, (3)the oxidation of phenanthraquinone. Fluorenone-carboxylic acids can beobtained by oxidation of fluoranthene with chromic acid, or by heatingisodiphenic acid with concentrated sulfuric acid, or from2'-aminobenzophenone-2-carboxylic acid by the action of nitrous acid.Fluorenone-1,7-dicarboxylic acid can be obtained by the action ofpermanganate on retene-quinone. Retene is defined as1-methyl-7-isopropyl-phenanthrene. These processes produce manyby-products.

As a result of these difficulties, considerable investigations have beencarried out in efforts to develop syntheses of anthraquinones andfluorenones whereby the desired products in good yield are obtained bysimple economic methods. This invention relates to a method forpreparation of anthraquinones and fluorenones in good yield. The processcan be by batch or by continuous method.

SUMMARY OF THE INVENTION

A process is disclosed for preparation of anthraquinones or fluorenonesand their substituted derivatives by oxidation under mild conditions ofthe corresponding 2-methyl-substituted biphenyls and diphenylmethanes inthe presence of an oxygen-containing gas and a cobalt-manganese-brominecatalyst at a temperature of from about 75° C. to about 250° C. at apressure of from about 1 atmosphere to about 100 atmospheres.

DETAILS OF THE INVENTION

This novel invention is a method to prepare anthraquinone andfluorenone, and their substituted derivatives by contacting2-methyl-substituted biphenyls and diphenylmethanes with a catalyticcomposition comprised of cobalt, manganese, and bromine compounds. Morespecifically, this invention is a method to prepare anthraquinone andfluorenone and their derivatives in good yield.

Our novel process relates to the liquid-phase air oxidation of2-methyl-substituted diphenylmethane to anthraquinone in a mother liquorcomprising an acetic acid medium wherein the weight ratio of2-methyl-substituted diphenylmethane to acetic acid is in the range offrom about 1:1 to about 1:20, preferably from about 1:4 to about 1:20,using cobalt, manganese, and/or other variable-valence metals, such aszirconium, plus bromine. Our novel invention is a process for theoxidation of 2-methyldiphenylmethane with molecular oxygen toanthraquinone under liquid-phase conditions in the presence of acobalt-manganese-bromine catalyst at a temperature within the range offrom about 75° C. to about 250° C. and a pressure from about 1atmosphere to about 100 atmospheres. Other compounds which may besuitable for oxidation by this process are 2-methylbenzophenone anddiphenylmethyl alcohols. The process can be by batch or continuousmethod.

In one aspect, our process can be a continuous process for producinganthraquinone by the liquid-phase air oxidation of2-methyldiphenylmethane in a mother liquor comprising an acetic acidmedium in the presence of a cobalt-manganese-bromine catalyst whereinthe mole ratio of cobalt to manganese is from about 1.0:0.1 to about1.0:10.0, and the mole ratio of bromine to total metals of thecobalt-manganese-bromine catalyst is from about 0.2:1.0 to about20.0:1.0, preferably from about 3.0:1.0 to 10:1.0, bromine moles tototal metal moles. The process can comprise conducting the reaction intwo stages comprising a first-stage reaction at a temperature of about75° C. to about 200° C. and a second-stage reaction at a temperature ofabout 150° C. to about 250° C., recovering the cobalt-manganese catalystby oxalate precipitation of the catalyst using about 0.25 to about 2.5moles of oxalic acid per total moles of cobalt and manganese andrecycling the recovered cobalt and manganese compounds to the oxidationstages. Preferably, the mole ratio of the oxalic acid to thecobalt-manganese catalyst is about 0.5 to about 1.5.

In another aspect, the present invention can be a continuous process forproducing anthraquinone by the liquid-phase air oxidation of2-methyldiphenylmethane in a mother liquor comprising an acetic acidmedium in the presence of a zirconium-cobalt-manganese-bromine catalystwherein the mole ratio of zirconium-to-cobalt in the catalyst is fromabout 0.005:1.0 to about 0.20:1.0, preferably from about 0.01:1 to about0.1:1.0, and the mole ratio of bromine to total metals of thezirconium-cobalt-manganese-bromine catalyst is from about 0.2:1.0 toabout 20.0:1.0, preferably from about 3.0:1 to 10:1, bromine moles tototal metal moles. The process can comprise conducting the reaction intwo stages comprising a first-stage reaction at a temperature of about75° C. to about 200° C. and a second-stage reaction at a temperature ofabout 150° C. to about 250° C., recovering thezirconium-cobalt-manganese catalyst by oxalate precipitation of thecatalyst using about 0.25 to about 2.5 moles of oxalic acid per totalmoles of zirconium, cobalt, and manganese and continuously recycling therecovered zirconium-cobalt-manganese compounds to the oxidation stages.Preferably, the mole ratio of oxalic acid to zirconium-cobalt-manganesecatalyst is about 0.5 to about 1.5.

In a continuous mode of operation, the catalyst is preferably recoveredand recycled. Since the catalyst metals may coprecipitate with theanthraquinone product during crystallization, our novel process caninclude a catalyst recovery process which comprises a high temperatureof about 110° C. to about 200° C. and an oxalate precipitation in aseparate step. In our recovery process, high cobalt recoveries can beexpected. Cobalt is the most expensive component of the catalyst.

In the recovery process, only small amounts of oxalic acid are required,usually about a 1:1 mole ratio with the catalyst metals; however, we canuse mole ratios of oxalic acid to total cobalt and manganese of about0.25:1 to 2.5:1. In our recovery process, the oxalate salts formrapidly, even from cobalt and manganese, or cobalt, manganese andzirconium, previously tied up as insoluble salts. The oxalates arereadily recovered from the acetic acid solvent, in which they areinsoluble, by high temperature separation, by, for example, highpressure centrifugation, or by hydroclones.

Temperatures in excess of about 200° C. cannot be used in our recoveryprocess, since the oxalate salts of cobalt, manganese and zirconiumdecompose. The thermal instability of the oxalate salts enables us torecycle these compounds to the 2-methyldiphenylmethane oxidationreactors. Under our process oxidation conditions of about 150° C. toabout 250° C., the oxalate salts regenerate to the active catalystmetals.

Our instant invented process also comprises a process for producingfluorenones from substituted biphenyls by the liquid-phase air oxidationof substituted biphenyls in a mother liquor comprising an acetic acidmedium to a fluorenone product wherein weight ratio of substitutedbiphenyl to acetic acid is in the range of about 1:1 to about 1:20,preferably from about 1:4 to about 1:20, pressure is in the range offrom about 1 atmosphere to about 100 atmospheres, in the presence of acobalt-manganesebromine catalyst or a zirconium-cobalt-manganese-brominecatalyst wherein the mole ratio of zirconium-to-cobalt in the catalystis from about 0.005:1.0 to about 0.2:1.0, preferably about 0.01:1 toabout 0.10:1. Mole ratio of bromine to total metals of thecobalt-manganese-bromine or zirconium-cobalt-manganese-bromine catalystis from about 0.2:1.0 to about 20.0:1.0, preferably from about 3.0:1.0to about 10.0:1.0, bromine moles to total metal moles. The process cancomprise conducting the oxidation in two stages, comprising afirst-stage reaction at a temperature of about 75° C. to about 200° C.and a second-stage oxidation at a temperature of about 250° C. whereinboth air and catalyst are added during the oxidation stages, recoveringthe cobalt-manganese metals or the zirconium-cobalt-manganese metals ofsaid catalyst by oxalate precipitation of metals of said catalyst, usingabout 0.25 to about 2.5 moles of oxalic acid for the total moles of thecobalt-manganese metals or zirconium, cobalt and manganese metals ofsaid catalysts and recycling the recovered cobalt-manganese compounds orzirconium-cobalt-manganese compounds to the oxidation stages.Preferably, mole ratio of said oxalic acid to said cobalt-manganese orzirconium-cobalt-manganese of said catalyst is about 0.5:1.0 to about1.5:1.0.

In summary, the instant invention comprises a process for producingcyclized aromatic compounds comprising anthraquinones and fluorenonesand carboxy derivatives of said aromatic compounds which processcomprises liquid-phase air oxidation of a feedstock selected rrom thegroup consisting of 2-methyldiphenylmethane, 2-methylbiphenyl andderivatives of said 2-methyldiphenylmethane and said 2-methylbiphenyl tosaid anthraquinones and fluorenones in a mother liquid comprising anacetic acid medium wherein weight ratio of said feedstock to acetic acidis in the range of from about 1:1 to about 1:20, in the presence of acobalt-manganese-bromine catalyst wherein the mole ratio of cobalt tomanganese is about 1.0:0.1 to about 1.0:10.0, and mole ratio of bromineto total metals of said catalyst is from 0.2:1.0 to about 20.0:1.0, theprocess comprising oxidation of said feedstock at a temperature withinthe range of from about 75° C. to about 250° C. at a pressure of fromabout 1 to about 100 atmospheres, preferably said weight ratio of saidfeedstock to acetic acid is in the range of from about 1:4 to about1:20, said mole ratio of cobalt-to-manganese is from about 1.0:0.1 toabout 1.0:10.0, and said mole ratio of bromine to total metals of saidcatalyst is from about 3.0:1.0 to about 10.0:1.0.

The instant invention also comprises a process for producing cyclizedaromatic compounds comprising anthraquinones and fluorenones and carboxyderivatives of said aromatic compounds which process comprisesliquid-phase air oxidation of a feedstock selected from the groupconsisting of 2-methyldiphenylmethane, 2-methylbiphenyl and derivativesof said 2-methyldiphenylmethane and said 2-methyldiphenyl to saidanthraquinones and fluorenones in a mother liquor comprising an aceticacid medium wherein weight ratio of said feedstock to acetic acid is inthe range of from about 1:1 to about 1:20, in the presence of azirconium-cobalt-manganese-bromine catalyst wherein the mole ratio ofzirconium to cobalt is about 0.005:1.0 to about 0.20:1.0; the mole ratioof cobalt to manganese is from about 1.0:0.1 to about 1.0:10.0, and moleratio of bromine to total metals of said catalyst is from about 0.2:1.0to about 20.0:1.0, the process comprising oxidation of said feedstock ata temperature within the range of from about 75° C. to about 250° C. ata pressure from about 1 to about 100 atmospheres, preferably said weightratio of said feedstock to acetic acid is in the range of from about 1:4to about 1:20, said mole ratio of zirconium to cobalt in said catalystis from about 0.01:1.0 to about 0.10:1.0 and said mole ratio ofcobalt-to-manganese is from about 1.0:0.1 to about 1.0:10.0, and saidmole ratio of bromine to total metals of said catalyst is from about3.0:1.0 to about 10.0:1.0.

The instant invention also comprises a continuous process for producingcyclized aromatic compounds by the continuous liquid-phase air oxidationof a feedstock selected from the group consisting of2-methyldiphenyl-methane, 2-methylbiphenyl and derivatives thereof toanthraquinones and fluorenones in a mother liquor comprising an aceticacid medium wherein weight ratio of feedstock to acetic acid is in therange of from about 1:1 to about 1:20, in the presence of acobalt-manganese-bromine catalyst wherein the mole ratio ofcobalt-to-manganese is about 1.0:0.1 to about 1.0:5.0, mole ratio ofbromine to total metals of the cobalt-manganese-bromine catalyst is fromabout 0.2:1.0 to about 20:1, bromine moles to total metals moles, theprocess comprising oxidation of said feedstock in two stages comprisinga first-stage oxidation at a temperature of about 75° C. to about 200°C. and a second-stage oxidation at a temperature of about 150° C. toabout 250° C. wherein both air and the cobalt-manganese-bromine catalystare added to said oxidation stages and recovering the cobalt-manganesemetals of said catalyst by oxalate precipitation of metals of saidcatalyst at temperatures of about 110° C. to about 200° C., using about0.25 to about 2.5 moles of oxalic acid for the total moles of cobalt andmanganese metals of said catalyst and continuously recycling the cobaltand manganese oxalates to said oxidation stages, preferably said weightratio of said feedstock to acetic acid is in the range of from about 1:4to about 1:20, said mole ratio of cobalt to manganese is from about1.0:0.1 to about 1.0:10.0, and said mole ratio of bromine to totalmetals of said catalyst of from about 3.0:1.0 to about 10.0:1.0.

The instant invention comprises a continuous process for producingcyclized aromatic compounds acid by the continuous liquid-phase airoxidation of a feedstock selected from the group consisting of2-methyldiphenylmethane, 2-methylbiphenyl and derivatives thereof toanthraquinones and fluorenones in a mother liquor comprising an aceticacid medium wherein weight ratio of feedstock to acetic acid is in therange of from about 1:1 to about 1:20 in the presence of azirconium-cobalt-manganese-bromine catalyst wherein the mole ratio ofzirconium-to-cobalt is about 0.005:1.0 to about 0.20:1.0, the mole ratioof cobalt-to-manganese is about 1.0:0.1 to about 1.0:5.0, and mole ratioof bromine to total metals of said catalyst is from about 0.2:1.0 toabout 20.0:1.0, which process comprises conducting the oxidation in twostages comprising a first-stage reaction at a temperature of about 75°C. to about 200° C. and a second-stage oxidation at a temperature ofabout 150° C. to about 250° C. wherein both air and thezirconium-cobalt-manganese-bromine catalyst are added to said oxidationstages and recovering the zirconium-cobalt-manganese metals of saidcatalyst by oxalate precipitation of metals of said catalyst attemperatures of about 110° C. to about 200° C., using about 0.25 toabout 2.5 moles of oxalic acid for the total moles of the zirconium,cobalt and manganese metals of said catalyst and continuously recyclingthe zirconium-cobalt-manganese oxalates to said oxidation stages,preferably said weight ratio of feedstock to acetic acid is in the rangeof from about 1:4 to about 1:20, said mole ratio of zirconium-to-cobaltin said catalyst is from about 0.01:1.0 to about 0.10:1.0, and said moleratio of said cobalt-to-manganese is from about 1.0:0.1 to about1.0:10.0, and said mole ratio of bromine to total metals of saidcatalyst is from about 3.0:1.0 to about 1.0:10.0.

The following examples illustrate the process of the instant inventionbut are not to be construed as limiting the scope of the invention.

EXAMPLE I

The following example illustrates the batch oxidation of2-methyldiphenylmethane. 1.64 g 2-methyldiphenylmethane (0.009 moles),100 ml acetic acid, 0.042 g cobalt acetate (0.00017 moles), 0.041 gmanganese acetate (0.00017 moles), and 0.103 g sodium bromide (0.0010moles) were added to a reactor. Reaction temperature was 194° F. (90°C.) at atmospheric pressure. The reaction was allowed to run for a fullperiod of seven (7) days. Removal of the acetic acid solvent byevaporation resulted in precipitation of the product,9-10-anthraquinone, which was determined by thin layer chromatographicanalysis on silica gel using methylene chloride as eluent versus theknown component.

EXAMPLE II

The batch procedure of Example I was repeated with 2.0 g of2-methyldiphenylmethane (0.011 moles) with the same catalyst at the sametemperature and atmospheric pressure. Reaction time was 7 days. Ratio ofcobalt to 2-methyldiphenylmethane (2-MDM) was 0.015 moles Co to eachmole of 2-MDM. Theoretical yield of 2-benzoylbenzoic acid was 2.49 g.Recovered solids were 1.30 g. Yield of anthraquinone was 7 mole%.Recycle of 2-benzoylbenzoic acid and subsequent cyclization in acontinuous method can increase yield of anthraquinone to approximately atheoretical 52 (mole) % yield based upon the solids recovery of 1.30 g.

EXAMPLE III

The batch procedure of Example I was repeated with 2.0 gtrimethylbiphenyl (0.010 mole) with the same catalyst at the sametemperature and atmospheric pressure. Reaction time was four (4) days(96 hours). Ratio of cobalt to trimethylbiphenyl was 0.017 moles Co permole of trimethylbiphenyl. Theoretical yield to tricarboxybiphenyl was2.86 g. Details are in Table I.

                  TABLE I                                                         ______________________________________                                        Preparation of 2,6-DCF                                                        Mole Ratios-Br:Catalyst Metals-3:1                                            ______________________________________                                        Catalyst                                                                      Co(OAc).sub.2 (0.0100 g Co; 0.00017 mole Co)                                                             0.042 g                                            Mn(OAc).sub.2 (0.0092 g Mn; 0.00017 mole Mn)                                                             0.041 g                                            NaBr (0.080 g Br; 0.0010 mole Br)                                                                        0.103 g                                            Feed                                                                          Trimethylbiphenyl (0.010 mole)                                                                           2.0 g                                              Acetic Acid                100 ml                                             Reaction Conditions                                                           Temperature                90° C.                                      Pressure, Atm.             1                                                  Time, Hours                96                                                 Product Recovery-Filtration                                                                              Hot                                                Ratio-Moles Br to Total    3:1                                                Moles Catalyst Metals                                                         Yields (wt) %                                                                 2,6-Fluorenonedicarboxylic Acid (2,6-DCF)                                                                11.5                                               2,4',5-Biphenyltricarboxylic Acid (TCBi)                                                                 70.1                                               2,6-Benzcoumarindicarboxylic Acid (BzC)                                                                  18.4                                               Total                      100.0%                                             Total Solids Recovered     1.24 g                                             Percent Theoretical Yield  43.4%                                              ______________________________________                                    

EXAMPLE IV

The procedure of Example III was repeated with an increase of NaBr to0.206 g (0.16 g Br; 0.0020 mole Br). All other conditions were the sameas in Example III. The increase in bromine concentration increased therelative weight percent of 2,6-DCF in the total solids recovered.Details are in Table II.

                  TABLE II                                                        ______________________________________                                        Preparation of 2,6-DCF                                                        Mole Ratio-Br:Catalyst Metals-6:1                                             ______________________________________                                        Catalyst                                                                      Co(OAc).sub.2 (0.0100 g Co; 0.00017 mole Co)                                                             0.042 g                                            Mn(OAc).sub.2 (0.0092 g Mn; 0.00017 mole Mn)                                                             0.041 g                                            NaBr (0.160 g Br; 0.0020 mole Br)                                                                        0.206 g                                            Feed                                                                          Trimethylbiphenyl (0.010 mole)                                                                           2.0 g                                              Acetic Acid                100 ml                                             Reaction Conditions                                                           Temperature                90° C.                                      Pressure, Atm.             1                                                  Time, Hours                96                                                 Product Recovery-Filtration                                                                              Hot                                                Ratio-Moles Br to Total    6:1                                                Moles Catalyst Metals                                                         Yields (wt) %                                                                 2,6-DCF                    34.1                                               TCBi                       51.1                                               BzC                        14.8                                               Total                      100.0                                              Total Solids Recovered     1.10 g                                             Percent Theoretical Yield  38.5%                                              ______________________________________                                    

EXAMPLE V

The procedure of Example III was repeated with an increase in thecatalyst metals present. All other conditions were the same as inExample III. The increase in catalyst metals concentration reduced therelative weight percent of 2,6-DCF in the total solids recovered.Details are in Table III.

                  TABLE III                                                       ______________________________________                                        Preparation of 2,6-DCF                                                        Mole Ratio-Br:Catalyst Metals-1:1                                             ______________________________________                                        Catalyst                                                                      Co(OAc).sub.2 (0.030 g Co; 0.00050 mole Co)                                                              0.125 g                                            Mn(OAc).sub.2 (0.028 g Mn; 0.00050 mole Mn)                                                              0.123 g                                            NaBr (0.080 g Br; 0.0010 mole Br)                                                                        0.103 g                                            Feed                                                                          Trimethylbiphenyl (0.010 mole)                                                                           2.0 g                                              Acetic Acid                100 ml                                             Reaction Conditions                                                           Temperature                90° C.                                      Pressure, Atm.             1                                                  Time, Hours                96                                                 Product Recovery-Filtration                                                                              Hot                                                Ratio-Moles Br to Total    1:1                                                Moles Catalyst Metals                                                         Yields (wt) %                                                                 2,6-DCF                    7.2                                                TCBi                       79.2                                               BzC                        13.6                                               Total                      100.0                                              Total Solids Recovered     1.35 g                                             Percent Theoretical Yield  47.2%                                              ______________________________________                                    

EXAMPLE VI

The procedure of Example III was repeated with a reduced amount ofsolvent acetic acid present. All other conditions were relatively thesame as in Example III by increasing the amount of catalyst andtrimethylbiphenyl present. The increase in total solids recovered wasconsidered to result from ease of handling the resulting larger quantityof product. Details are in Table IV.

                  TABLE IV                                                        ______________________________________                                        Preparation of 2,6-DCF                                                        Low Solvent-Br:Catalyst Mole Ratio-3:1                                        ______________________________________                                        Catalyst                                                                      Co(OAc).sub.2 (0.030 g Co; 0.00050 mole Co)                                                              0.125 g                                            Mn(OAc).sub.2 (0.028 g Mn; 0.00050 mole Mn)                                                              0.123 g                                            NaBr (0.240 g Br; 0.0030 mole Br)                                                                        0.309 g                                            Feed                                                                          Trimethylbiphenyl (0.03 mole)                                                                            6.0 g                                              Acetic Acid                44 ml                                              Reaction Conditions                                                           Temperature                90° C.                                      Pressure, Atm.             1                                                  Time, Hours                96                                                 Product Recovery-Filtration                                                                              Hot                                                Ratio-Moles Br to Total    3:1                                                Moles Catalyst Metals                                                         Yields (wt) %                                                                 2,6-DCF                    14.9                                               TCBi                       79.1                                               BzC                        6.0                                                Total                      100.0                                              Total Solids Recovered     5.59 g                                             Percent Theoretical Yield  65.2%                                              ______________________________________                                    

EXAMPLE VII

The procedure of Example III was repeated but temperature was increasedto 435° F. (224° C.), reaction pressure to 500 psig (33.4 atm) andreaction time decreased to 30 minutes. The bromine to catalyst metalsratio was 11:1, manganese to cobalt mole ratio was 3:1. Cobalt totrimethylbiphenyl ratio was reduced to 0.0035 moles Co to 1 mole oftrimethylbiphenyl. Details are in Table V.

                  TABLE V                                                         ______________________________________                                        Preparation of 2,6-DCF                                                        High Mn:Co ratio-High Br:Catalyst Metals Ratio                                ______________________________________                                        Catalyst                                                                      Co(OAc).sub.2 (0.026 g Co; 0.00044 mole Co)                                                              0.11 g                                             Mn(OAc).sub.2 (0.074 g Mn; 0.00135 mole Mn)                                                              0.33 g                                             HBr (48%) (1.56 g Br: 0.0196 Mole Br)                                                                    3.3 g                                              Feed                                                                          Trimethylbiphenyl (0.127 mole)                                                                           24.8 g                                             Acetic Acid                800 ml                                             Reaction Conditions                                                           Temperature, °F.    435                                                Pressure, psig             500                                                Time, min.                 30                                                 Product Recovery-Filtration                                                                              Hot                                                Ratio-Moles Br to Total    11:1                                               Moles Catalyst Metals                                                         Ratio-Co:Trimethylbiphenyl (Moles)                                                                       0.0035                                             Yields (wt) %                                                                 2,6-DCF                    28.5                                               TCBi                       39.3                                               BzC                        32.2                                               Total                      100.0                                              Total Solids Recovered     9.0 g                                              Percent Theoretical Yield  25.3%                                              ______________________________________                                    

What is claimed is:
 1. A process for producing cyclized aromaticcompounds comprising anthraquinones and fluorenones and carboxyderivatives of said aromatic compounds which process comprisesliuqid-phase air oxidation of a feedstock selected from the groupconsisting of 2-methyl-diphenylmethane, 2-methylbiphenyl and derivativesof said 2-methyldiphenylmethane and said 2-methylbiphenyl to saidanthraquinones and fluorenones in a mother liquor comprising an aceticacid medium wherein weight ratio of said feedstock to acetic acid is inthe range of from about 1:1 to about 1:20, in the presence of acoblat-managanese-bromine catalyst wherein the mole ratio of cobalt tomanaganese is about 1.0:0.1 to about 1.0:10.0, and mole ratio of bromineto total metals of said catlayst is from 3.0:1.0 to about 10.0:1.0, theprocess comprising oxidation of said feedstock at a temperature withinthe range of from about 75° C. to about 250° C. at a pressure of fromabout 1 to about 100 atmospheres.
 2. The process of claim 1 wherein saidweight ratio of said feedstock to acetic acid is in the range of fromaobut 1:4 to about 1:20.
 3. A continuous process for producing cyclizedaroamtic compounds by the continuous liquid-phase air oxidation of afeedstock selected from the group consisting of 2-methyldiphenylmethane,2-methylibiphenyl and derivatives thereof to anthraquinones andfluorenones in a mother liquor comprising an acetic acid medium whereinweight ratio of feedstock to acetic acid is in the range of from about1:1 to about 1:20, in the presence of a cobalt-mangance-bromine catalystwherein the mole ratio of cobalt-to-managanse is about 1.0:0.1 to about1.0:5.0, mole ratio of bromine to total metals of the cobalt-manganesebromine catalyst is from about 3.0:1.0 to about 10.0:1.0, bromine molesto total metals moles, the process comprising oxidation of saidfeedstock in two stages comprising a first-stage oxidation at atemperature of about 75° C. to about 200° C. and a second-stageoxidation at a temperature of about 150° C. to about 250° C. whereinboth air and the cobalt-manganese-bromine catalyst are added to saidoxidation stages and recovering the cobalt-manganese metals of saidcatalyst by oxalate precipitation of metals of said catalyst attemperature of about 110° C. to about 200° C., using about 0.25 to about2.5 moles of oxalic acid for the total moles of cobalt and manganesemetals of said catalyst and continuously recycling the cobalt andmanganese oxalates to said oxidation stages.
 4. The process of claim 3wherein said weight ratio of said feedstock to acetic acid is in therange of from about 1:4 to about 1:20.
 5. In an improved process forproducing cyclized aromatic compound comprising anthraquinons andfluorenones and carboxy derivatives of said aroamtic compounds wherein afeedstock selected from the group consisting of2-methylidiphenylmethane, 2-methylbiphenyl, and derivatives of said2-methyldiphenylmethane and said 2-methylbiphenyl is oxidized in theliquid phase in a mother liquor comprising an acetic acid medium in thepresence of a cobalt-manganese-bromine catalyst to said anthraquinonesand fluorenones, the improvement which comprises employing a catalystproviding a bromine-to-total metals mole ratio that is within the rangeof about 3.0:1.0 to about 10.0:1:0.